Not sure why you are doing this in the first place.
For Powershell, there is no need to load up the PATH variable when you can use profiles and aliases. The performance cost is the prompt having to search each folder when it looks for commands.
Then there is a practicality cost. Path is a global variable. Why use it to solve something that is only used by Powershell and the console? A global solution to a local problem generally leads to unforseen consequences.
Another unintended consequence is if you mistype a command and the system ends up launching a file from outside your working directory. It is just a pain in the rear and also a security vulnerability.
BTW, while the OS has a limit of 32,767 for the PATH variable, the Command Prompt has a much much shorter length, somewhere around 2,000. I don't know the exact numnber.